Hack saw frame



J. H. DHNER HACK SAW FRAME Jan. ll, 1952 Filed Aug. 14, 1947 191?. i ZJZaULe' INVENTOR ATTORNEYS;

' notches 2 I.

gages the washer I8' as clearly shown in Figure 3.

The back 6 of the outer frame section 5 is, as clearly shown in Figure 1, formed with a plurality of spaced notches 2|, in any of which cam disc I1 can be engaged. These notches are selected for engagement with the cam disc according to the length of a blade B to be carried by the frame.

Formed in the thinnest part of the cam disc II, for receiving the back 6, is a notch 22. From this, it is' seen that if the user partially rotates the handle portion of the hack saw relative to the outer frame section 5 thereof, notch 22 can;

be presented to the back 6, so that the back G may be adjusted in eimer direction'unm' 'melde-Y' sired notch 2| thereof is positioned for ,engagement by the cam disc. Returning of the handle portion of the device to its normal position when* 4 is partially rotated relative to the telescoping frame sections, so that notch 22 is presented to back 6. This permits free movement, of the frame sections relative to each other, and a blade B of desired length is then selected and attached as previously described. The desired notch 2I will by this operation have been presented to cam disc I1. The basic adjustment for length of the .f rame., is accordinglymade, and there is now effected .a preliminary tension adjustment.

This is made by threading the adjusting sleeve 9 forwardly, while the handle portion is still in offset position relative to the rest of the frame.

results in engagement of the cam disc vin the notch 2|, and such return results in the thickest portion of the disc being eng'aged in the notch, when the handle portion is 'fullyreturned to its normal position. Further movement 'in the same direction is limited by lugs 23 projected from opposite sides of the cam disc I1.

Itis to be noted at this point, and referring particularly to Figure 1 :or 3, that the thickest portion of the cam disc used in regulator operation of the device for the purposes stated is nevertheless of smaller width than any of the Other portionsof the disc, not used in normal operation of the device in effecting tension adjustment may be thickened or inclined forwardly as desired, this being for the purpose of preventing fully free rotation of the handle portion of the frame.

At 24 is shown a shallow indentation formed in the inclined face of the cam disc, `this being formed immediately adjacent lugs 23, as clearly shown in Figure 4. This serves asl a locking indentation, in a marmer to be described hereinafter.

Referring now to the means embodied in the invention for attaching the blade B, the free ends of arms 'I and 8 are enlarged as at 25, and have inwardly extended portions 26 projected toward eachother. In each of the portions 26 is formed a relatively large opening 21, with which communicates a closed slotl 28 ofsuiiicient length and width to receive the end of blade B. `Between enlargement 25 and opening 21 is formed 4It is thus seenihat if it 1s desiredt attach a foredoingvso, however, ring 32 is rotated so that the open part thereof is positioned against the slot 28, thuspermitting entri7 of blade B. When .the blade has been inserteda suflicient extent so that the usual opening therein presents itself to "the, ends of the ring, the'ring 32 is rotated a sucient extent, so as to preferably assumel the position shown in Figure 5. It may be observed I'that even though no tension lhas been placedv upon the frame, the spring l'engagingy'each of the rings 32 vwill prevent movement'threof except `upon theexertion of a positive manual pressure 'tov rotate the ring.

in the use of the khack saw constructed in accordance with the invention-the` handle portion Ril Yet() blade B, the end of the blade is inserted through slot 23y so as to project intothe opening 21. Be-

y When the adjusting sleeve is threaded forwardly in this manner, it will be seen that it will carry V*with it the handle portion of the device, having 'thereon cam disc I1, these being thus adjusted forwardly relative to the outer and inner frame sections;

When the adjusting sleeve has been threaded forward a desired distance, the handle section of the device is returned to its normal position, and in doing so, the L member 5 will be pressed away from the inner frame section, placing a strong tension upon the blade B. When the handle section has been fully returned to its normal position, the shallow indentation 24 will engage in notch 2I, or more properly one wall thereoig'with the partsthus being locked in desired position and under suitable tension;

` Mention is here made of spring I2. While this spring is not essential tothe operation of the invention, it is preferred to use it particularly Where a quick thread connection is employed between the inner barrel I0 and adjusting sleeve I9, since the spring I2 can thus at all times urge the connected members away from each other in the event of any looseness in the connection, particularly after long operation of the device.

Particular importance is placed upon the ease of operation in effecting a proper tensioni adjustment, wherein the user is required to make only a preliminary adjustment, the extent of which is capable of being visually determined, or by trying the cam disc against the wall of notch 2I. Having threaded the outer barrel'IS carrying cam disc I1 forwardly in making this rough adjustment, it is only necessary to swing the handle back into normal position, this action automatically placing the whole frame under strong tension and locking the parts together.

What is claimed is:

1. In a hack saw relatively slidable inner` and outer frame sections, the outer. section having a back portion formed with-'notches spacedlongitudinally thereof; a blade -connected at -Opposite ends to the respectivelsections; a spindle rigid at one end with and extending away from the inner frame section in parallelism with andbelow said back portion; an outer barrel mounted on the spindle for rotation and for sliding movement longitudinallyof the spindle; a handle rigid with and extending laterally from the outer barrel; a' cam disc having an inclined face` rigid with and surrounding the outer barrel, said disc being engageable in any of said notches; and means movably mounted on said spindle and engageable with the barrel to shift the barrel'slidably andlongitudinally'of the spindle, whereby to transmit slidable movement to the outer frame section4 through the medium-of the cam disc' and notch" engagement for preliminary tensioning vof the blade, the handle and barrel being rotatable in the position to which the barrel i'seslidably moved for camming engagement of the inclined face of the disc with the wall of the notch whereby to impart additional sliding movement to said outer frame section and eect final tensioning of the blade.

2. In a hack saw relatively slidable inner and outer frame sections, the outer section having a back portion formed With notches spaced longitudinally thereof; a blade connected at opposite ends to the respective sections; a spindle rigid at one end with and extending away from the inner frame section in parallelism with and below said back portion, the other end of the spindle .being threaded; an outer barrel mounted on the spindle for rotation and for sliding movement longitudinally of the spindle; a handle rigid with and extending laterally from the outer barrel; a cam disc having an inclined face rigid with and surrounding the outer barrel, said disc being engageable in any of said notches; and an adjusting sleeve threaded on the spindle and engaging the barrel to shift the barrel slidably and longitudinally of the spindle whereby to transmit slidable movement to the outer frame section through the medium of the cam disc and notch engagement for preliminary tensioning of the blade, the handle and barrel being rotatable in the position to which the outer barrel is slidably moved for camming engagement of the inclined face of the disc with the wall of the notch whereby to impart additional sliding movement to said outer frame section and effect nal tensioning of the blade.

3. A hack saw comprising an inner frame section; a sleeve formed thereon; an outer frame section having a back portion slidable in the sleeve, there being a plurality of Widely spaced notches formed in and disposed longitudinally of said back portion; a blade connected at opposite ends to the respective frame sections; a spindle rigid at one end with and extending away from the inner frame section in parallelism .with and below said back portion, the other end 0i the 6 spindle being threaded, the spindle having a smooth-surfaced medial portion; a spacer sleeve mounted on the medial portion of the spindle to slide longitudinally thereof; an outer barrel mounted rotatably on the spacer sleeve and having a shoulder engaged by one end of the spacer sleeve to shift the barrel longitudinally of the spindle with the spacer sleeve; a handle rigid with and extending laterally from the outer barrel; a cam disc having an inclined face rigid with and surrounding the outer barrel, said disc being engageable in any of said notches; and an adjusting sleeve threaded on the threaded end of the spindle and engaging the other end of the spacer sleeve to shift the spacer sleeve longitudinally of the spindle, whereby to transmitl REFERENCES CITED The following references are of record in the le of this patent:

UNITED 'STATES PATENTS Number y Name Date 878,160 Stebbins Feb. 4, 1908 1,950,973 Cross Mar. 13, 1934 FOREIGN PATENTS Number Country Date 58,508 Sweden Mar. 24, 1925 53,152 Sweden Dec. 6, 1932 94,123 Sweden 1-a Jan. 9, 1939 

